Electrical fuse



J. L. LEHNHERR ELECTRICAL FUSE Oct. 25, 1938.

Original Filed Feb. 15, 1952 2 Sheets-Sheet l INVbNTOR JuneL.L.ehn7-ierr Oct. 25, 1938. J. L. LEHNHERR ELECTRICAL FUSE OriginalFiled Feb. 15, 1932 2 Sheets-Sheet 2 Patented Oct. 25, 1938 i t2,134,523

UNITED STATES PATENT OFFICE 2,134,523 ELECTRICAL FUSE June L. Lehnherr,Eldorado, Kans, assignor to Westinghouse Electric& ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationFebruary 15, 1932, Serial No. 592,947

Renewed October 1'7, 1935 7 Claims. (Cl. 200-117) This invention relatesto an improvement in incident to the failure of the fuse. For instance,electrical fuses such as are used in connection the failure of the fusemight set off an alarm syswith transformers, power transmission linesand tem, or it might, in the case of the blowing of one the like,although they may be designed for other fuse, operate a relay whichwould open the other 5 purposes as will be later explained. phases of apolyphase circuit. 6 Fuses for use as above mentioned have been Anotherfeature of my invention is that it permade before but they have not beenaltogether mits the use of a very short fuse element, thussatisfactory'as their working parts have been in-' reducing the cost ofrefusing. My device may also terfered with by weather conditions, suchas ice be used over and over again and will provide over- 10 freezing inthe working parts which prevents acload protection as well as fuseprotection.

tion of the parts and defeats. the purpose of the My device will extendthe field of fuses and will fuse. This trouble is overcome by the use ofmy invade the oil circuit breaker field since it will improved device.provide asimple, economical means of quickly My improved fuse devicedoes away with set breakin an e t a Circuitscrews, bolts, etc., leavingthe exterior of the. This device will find its place in fusing of powerfuse tube neat and doing away with the demand or potential transformers,line sectionalizing or for special tools in reloading the fuse. whereverit is desirable to interrupt an electric Another feature of my improvedfuse device current at a predetermined rate of current flow.. is thatafter the parts of the fuse are assembled, While the int rnal pa ts ofmy f device the fuse tube is closed so that it is tight and pracelfexpelling they will have the assistance 'of 20 tically weather proof,thereby keeping the interior y. r the explosion of he fuse in the of thetube dry and the parts therein in operative Chamber, both, in assistingto make a q ck condition at all times. The fuse tube being sointerruption of the eileuitclosed also prevents insects, dust, or othermatter y device Provides, through the pos t e S o k entering orcollecting in the tube which might inimpact of the Spring Dhmger,eerteihp terfere with th functi n of th fuse, tion of the fuse for outdoorfuses during sleet or A further featu e of my improved fuse d i is icestorms. Another advantage is that the lower that the fuse element isheld in tension in the or Contact and Sealing D 8 earl be recessed Sltcenter of the fuse tube or barrel thereby eliminaty Q minimize theforming of ice a the j t y th t of th between the contact plug and thefuse housing.

3O ing the burning of the barrel b fu element However, even though icemay form at this loca- A t feature of my i ti i t t t {use tion, thepositive action of the device will break.

assembly is entirely self contained and no part any ice formed andinsure e C n f the of th fuse 1m it lf, or pig-tail c n t is fuse tubeof all metallic content. This is particuexposed to the weather. Thisfeature eliminates lerlv desirable on disconnect or sectionalizing s:-corrosion of the metal or crystallization from Switches which depend fortheir rupturing p w r i d b t on the drop out principle of the entirefuse as- A still further feature of my improved fuse desembly- In caseOf sleet, the toggle other t holding the fuse assembly viceis that thehammer or impact principle eme ae l a rangemen bodied therein insurespositive clearance of the 111 Place may freeze p and fell to Operate The40 interior of the tube of all metallic elements, sepause Of y Selfexpulsion ch nical device will rating the two parts of the electriccircuit by the insure the rupturing 0f the fusefull length of thenon-conducting fibre or There may be cases where it is inadvisable toposition t have the fuse device completely expelled from Another featureof my invention is that the det tube- In this case. w r. h sp in action45 vice provides a simple method of refusing the tube i v lv d will inure the nlar em n f h p by a simple positive means, and the device isafter the failure of the fuse element.

adaptable to fuses of any size and for tubes which The construction ofthis fuse device and its asare enclosed in an exterior housing as wellas sembly with the other elements to make up the 60 tubes exposed to theweather. complete fuse are such that it gives a positive A still furtherfeature of my improved fuse is continuous metallic circuit from one endof the that through the impact or kinetic energy of the fuse to theotherthus eliminating radio interferdevice in expelling itself from thetube it may be ence, which is a common defect of many types of used tooperate ratchets,pawls or relays to accomfuse. plish any number or trainof operations desired Now referring to the e-wings in which like 66assembly as seen from the line I l [-1 H in Fig. 1. Fig. 4 is a planview ment 2| being long enough to reach from the top to the bottom ofthe tubular element H when the rod I6 is slid downward in the tubularelement It. From experimentation it has been and to theupper end 01' thepipe element H at a point 270 degrees around the pipe I.

On the upper end of the rod I8 and rigid thererigidly attached to the"pig-tail 24. The upper end rigidly attached to the lower pig-tail, orflexible copper upper end 01' the of the wire 21 is end of a second wire2 'upper side of the On the upper end of the tube "I is a metallicferrule 30 having an internal thereon which forms a channel 38 aroundthe plug 34. At 39 is a notch in the flange 31. The upper end of the"pig-tail 29 is passed through the cone opening 35 and the hole 36 thenpulled upwardly until the pin in the lower end of the rod is is liftedto the 15 in the tube H is pulled on the fuse elements 24, 25, 28, 21and 29 at which time the "pig-tail" 29 is bent over and caught in thenotch 39 and passed around in the channel 38 and tied to temporarilyhold against the tension of the spring H. The cap 33 is now screwed onthe portion 32 of the ferrule so that the interior top of the cappresses against the pig-tail 29 and firmly binds it between the cap andthe flange 31.

a drip to prevent ice forming between the plug I3 40 purposes abovedescribed.

In large fuse element 23 and wire, etc., one end of which the wire 22and the other end being rigidly aty tached to the pin 20a which is amxedto the rod tube H as previously described in Fig. 2. 7o

t that the device may fusible link 28 and be heated and melted with suchrapidity-that it might even pass off in a gaseous form; even the wires26 and 21 might be similarly affected, and raise a gas pressure in thetube In and blow the plug l3 and its attached parts out of the tube Hi.There is another action taking place simultaneously with that justdescribed. It is as follows: Upon the rupture between the wires 26 and21, the spring contracts, driving the rod |6 downward until the lowerend of the rod l6 strikes the plug l3, as shown in Fig. 5, causing animpact thereon and driving the plug l3 out of the ferrule therebyclearing the tube In of all metallic material and leaving a gap in thecircuit the length of the tube l which is too much for the current tojump or are thereby effecting a certain and positive break in thecircult.

There are circumstances where the overload on the conductors 43 and 44is brought on gradually and the violent destruction or blowing of thefuse as above described does not occur, instead, the overload slowlyincreases and the wires 26 and 21 gradually heat and-eventually reach apoint where the tension of the spring l1 pulls the wires 26 and 21apart,whereupon the impact of the rod IS on the plug |3 instantly takesplace and the plug I3 and attached parts are driven out of the tube Inleaving a gap the length of the tube Ill in the circuit as previouslydescribed.

In Figs. 2, 5 and 8 are shown the plunger type of impact producingmechanism, while in Fig. '1 is shown a simpler form to accomplish thesame result. Referring to Fig. 7, is shown the tapered plug |3a, whichcorresponds to the plug I3 in Fig. 2, and rigidly attached to the plug|3a is a metallic spring element l'lb, said spring element I'Ib having ahook like portion 23b formed on the top end thereof to which thepig-tail is tied as previously described.

In all of the types of impact producing devices shown, the impact issufficient to throw the whole impact producingdevice out of the tube l0and leave it free of any metallic material, this operation will occureven though the tube l0 may occupy an inclined or even an invertedposition.

Inasmuch as the impact producing mechanism is expelled from the tube IDwith such force as above described, thedevice becomes still more useful.It may enter the field of setting off alarms, or other trains of actionsuch as illustrated in Fig. 9 in which the fuse has been blown and theimpact producing device has been driven from the tube l0 and the plug l3strikes the handle or blade 46 of a switch driving the blade 46 tocontact the element 41 to complete a circuit between the conductors '48and '49 to operate signals, relays or other desired devices. The element46 might be a. trigger which when struck by the plug i3 would release acircuit breaker thereby opening all phases of a polyphase circuit; orthe element 46 might be a trigger which when struck by the plug l3 wouldrelease a train of mechanical actions or the like.

The characteristics of my fuse device are such I be employed in fieldsother than electrical, for instance, the walls of one end of the tubemight be left open as at like so that external flames of fire or heatwould melt the release the impact producing device and the plug |3 wouldstrike a fire alarm switch such as illustrated in Fig. 9 and close theswitch and thereby send out a fire alarm; or the plug l3 might strike atrigger 46 or 46' in Fig.

to release fire extinguishing devices 50 of one charactelt or another.

In Fig. 10 is shown my the tubular element II] is provided with openingslflrc, as above mentioned, thereby leaving the fuse 28 open to exteriorconditions. As shown the fuse has been melted by outside heat as from aflame, not shown, and the sealing plug l3 has been driven from its seatin the element II and has struck the trigger 46 which retained an arm 5|in the dotted position 5|. The arm 5| is mounted on a shaft 52 which isadapted to turn in a clockwise direction, when the arm 5| is released,by reason of the weight 53 which is suspended by a cable 54 which isattached to the fuse device in which sector 55 which is rigidly attachedto the shaft 52.

On the shaft 52 is a series of arms 56, 51, and 58 all of which arerigidly mounted on the shaft. At 59 is a link connecting between the arm56 and an electric switch 51 and is adapted to close the switch tocomplete a circuit upon the rotation of the shaft 52.

At 6|] is a shaft having a crank 6| on which is a connecting rod 62. Onthe shaft 60 is rigidly mounted an element 63 having a stop notch 64.The shaft 6|] is adapted to be rotated by any source of power, asillustrated, the source of power is a cable 65 wrapped around the shaft60 and on one end of the cable is a weight 66. At 61 is a stop baradapted to catch under the notch 64 and prevent the rotating of theshaft 60. One end of the stop bar 61 is pivotally connected at 68 to thearms 51 which, when the shaft 52 is turned, draws the bar 61 fromengagement with the notch 64 thereby permitting rotation of the shaft60.

At 50 is a water valve having an operating arm 69 which is connected tothe arm 58 by the link 10 and upon rotation of the shaft 52 the valve56is opened to permit the flow of water I The above description of thesethree operations is only illustrative of a train of operations that cantake place as a result of the failure of the fuse 28.

It will be understood that all such modifications of my improved fusedevice as have been mentioned above as well as those which lie withinthe scope of the appended claims may be employed without departing fromthe spirit and intention of my invention.

Now having fully described my invention, what I now claim and desire tosecure by Letters Patent 1. In an electrical fuse device, anonconducting enclosure, contact elements on the ends of said enclosure,a fuse element, means in one of said contact elements to hold said fuseelement on the central axis of the said enclosure, meansin the othercontact element to receive a-sealing plug, a spring actuated impactingdevice on said sealing plug and means for attaching said fuse element tosaid impacting device so that the tension of the spring in the impactingdevice will hold the fuse element under tension and hold the sealingplug in position in the contact element for the purpose described.

2. In an electrical fuse device, a non-conductmg enclosure, contactelements on either end thereof, said contact elements being joinedtogether by the combination of a fusible element and an impact producingdevice, said fusible element and impact producing device being containedin said enclosure, said impact producing device comprising a plug whichfits snugly. in one of said contact elements to form a comparativelyweather-proof joint between said plug and contact element, a tubularelement rigidly attached to said plug and having a slot in the side ofsaid tube, a rod slidable in said tube and a spring conneoted betweensaid tube and rod for causing said rod to strike said plug and drive theplug out of its socket in the contact element, a pin on said rod, saidpin passing through said slot and adapted to slide up and down therein,and a flexible connection between said pin and said tubular element,means on the upper end of said rod for connecting a fuse elementthereto, means for tenand rupture of said fuse element the said rod willbe released and caused to strike the said plug by reason of the springaction and drive the plug and its associated parts from its socket andclear the enclosure of all metallic material, substantially as describedand for the purpose set forth.

3. In a fuse device, an elongated housing having openings thereinintermediate its ends, a fuse element in said housing, said fuse elementbeing exposed to the exterior of said housing through said openings,means in one end of said housing for the support of a spring actuatedimpacting site end of said housing secured to one end of said fuseelement and normally held in operative position thereby, said springactuated impacting device being driven from the housing upon the ruptureof said fuse element.

4. In an electrical fuse device, a non-conducting housing, an electrical,contact element on each end of said housing, a fuse element and aspring actuated impacting device in said housing, a closure membercarried by said impacting device for sealing one end of said housing,said fuse eleated impacting member and be housing.

5. In an electrical fuse device, an insulation enclosure, contactelements on the enclosure. a fuse element, means associated with one ofsaid contact elements to hold said fuse element in spaced relation withsaid enclosure, a trigger releasing member associated with the othercontact element, an impact member on said trigger releasing member,spring means for biasing said impact member towards said triggerreleasing member and means for attaching said fuse element to saidimpact member so that said spring means will normally hold the fuseelement under the latter upon destruction of the fuse element.

6. In an electrical fuse device, an insulating enclosure, contactelements in spaced relation on the enclosure, a fuse element, meansassociated with one of the contact elements to hold said fuse element inspaced relation within said enclosure, means on the other contactelement to receive a sealing plug, a spring actuated impacting deviceassociated with said sealing plug, and means for attaching said fuseelement to said impacting device so that the spring of the impactingdevice will normally hold the fuse element under tension and hold thesealing plug in position in the enclosure, said spring being effectiveto cause actuation of the impacting device when the fuse is disrupted.

7. In an electrical fuse device, a tubular enclosure of insulatingmaterial, a contact element adjacent each end of the enclosure, afusible element within said enclosure, means for securing one end ofsaid fusible element to one of said contact elements, a closure memberadapted to nor,- mally engage said other contact element, a springactuated impacting device carried by said closure member and extendinginto said tubular enclosure and means for attaching the other end ofsaid fusible element to said impacting device so that the tension of thespring in said impacting device will hold the fusible element undertension and hold said closure member in position with respect to saidother contact element.

JUNE L. EHNHERR.

